The present invention relates to a dispensing process and apparatus particularly for a sealing/adhesive product.
As is known, the distribution of an adhesive or sealing/adhesive product on an item such as a mechanical part of a motor vehicle is currently performed manually or, in the most modern industries, by means of a robotized application.
In the first case, the problem which occurs arises, as well as from the need to use specialized personnel for this purpose, from the fact that the distribution of the adhesive or sealant/adhesive may not be performed uniformly and optimally, since it is subject to numerous variables which predominantly depend on the so-called "human factor."
In the second case, the problems which occur arise from the difficulty in distributing the adhesive or sealant/adhesive uniformly on the part, taking into account the numerous variables which determine a continuous variation in the viscosity of the product.
The greatest disadvantage of robotized application is the fact that the sealant/adhesive distributed on the part can frequently have one or more discontinuities essentially due to air bubbles. The reasons for which air bubbles are present in the sealing/adhesive product, which is for example of the anaerobic type, can be caused by the replacement of an empty can with a full one, a badly performed bleeding, or can be produced by an anomalous operation of the pumping system, or also, by the failure to signal the depletion of the product inside the can.
The bubbles which enter the circuit of the robotized system can, depending on the diameter of the tubes, on their length and on the deposited amount thereof, occur many times in different sizes and in successive moments during the distribution of the sealant/adhesive on the part. The consequent result is that the details executed, especially when sealing is required, are rejects.
It furthermore sometimes occurs that the bubbles are inside the already distributed sealant/adhesive, thus preventing an effective verification of the quality of the sealed product and producing harmful future consequences.
One thus observes an increase in costs and low production quality which is certainly not desired by manufacturers.
In order to at least partially obviate the disadvantage due to rejection, and more precisely to the temporary removal of the part from the production line, solutions have been tested in which a system for sensing the passage of air bubbles before the distribution of the product is adopted.
This sensing system stores the step of the robot's program in which the anomaly (air bubble) occurred and automatically returns to the portion where discontinuity in distribution occurred, restoring the missing product.
In this case the rejection of the part is eliminated, but on the other hand the sealing times are increased considerably, with a consequent slowing of the entire assembly line, especially in the field of motor vehicles, where the problem is most severely felt.
As can be easily imagined, the slowing and the increase in sealing times causes an increase in production costs which can even make the system as described above, which entailed the temporary removal of the defective part from the production line, more economical.
In this situation, the technical aim underlying the present invention is to solve the above described disadvantages of the known art.
Within the scope of this technical aim, an important object of the present invention is to provide a dispensing process and apparatus particularly for a sealing/adhesive product which eliminates the presence of air bubbles therein during the sealing of motor vehicle mechanical parts, such as gearshifts, engines and the like.
Another important object of the present invention is to provide a dispensing process and apparatus particularly for a sealing/adhesive product which eliminates the rejection of possible mechanical parts wherein the sealing is defective due to the presence of air bubbles and/or to avoid the restoring of the missing product with a subsequent pass.
Still another object of the present invention is to provide a dispensing process and apparatus particularly for a sealing/adhesive product which distributes an anaerobic sealant/adhesive with absolute precision and in a preset amount, independently of the variation of its chemical-physical characteristics.
Yet another object of the present invention is to provide a dispensing apparatus particularly for a sealing/adhesive product which has a high degree of reliability and therefore can operate in absolute safety on production lines without causing idle times due to possible problems and can furthermore be used with robots of different types according to the dimensions of the part to be sealed.